1. Field of the Invention
The present invention relates to protective window coverings and, more particularly, to a reinforced burglar- and storm-resistant cover for windows and doors.
2. Description of Related Art
It is often desirable to protect the windows, doors, and other openings of homes and business establishments from intrusion by unwelcome elements. Protective covers are used to secure an area from burglary and vandalism, and also to provide protection from weather-related effects such as violent storms or hurricanes. Conventional covers used for this purpose include rolling protective shutters which are constructed of a plurality of interconnected elongate slats or louvers.
In one form, a protective cover includes a frame which houses a plurality of L-shaped louvers which are deployable to form a curtain which covers the opening. One such protective cover is disclosed in U.S. Pat. No. 5,316,065 to Alligood. The louvers disclosed in the Alligood patent have a horizontal flange through which support and deployment cables pass, and a vertical flange extending downwardly from the horizontal flange proximate the front of the cover. The louvers are retained within a pair of tracks and an upper housing in a retracted position when the window, door, or other opening is exposed. In this position, the louvers are stacked one on top of another, with the stack having a combined thickness equal to the width of a horizontal flange plus the thicknesses of each of the vertical flanges. Accordingly, channels in the tracks dimensioned to accommodate the combined thickness of the stacked shutter.
To provide protection for the door or window, the louvers are lowered to a deployed position, thus forming a curtain which covers the opening. In the deployed position, the louvers are spaced such that the vertical flange of one of the louvers overlaps the louver immediately below. In this way, the curtain formed by the louvers completely covers the opening.
Positive pressure is caused by high speed winds blowing against the outside of the building and the shutter curtain. The Alligood shutters can withstand wind loads up to at least about 250 mph.
As positive pressure is created on one side of the building, negative pressure is created on the opposite side of the building as the high speed winds pass over and around the building. The negative pressure on the opposite side of the building is significantly less than the pressure inside the building and may pull out the walls, windows and roof if the pressure in the house is not equalized to match the negative pressure. To equalize the pressure, the vertical flanges of the Alligood shutters instantly deflect outwardly slightly from the overlapped horizontal flanges to place the interior of the building in fluid communication with the exterior. In this way, the pressure differential decreases as the internal pressure equalizes with the negative pressure, thereby preventing the walls, windows and roof from being pulled away from the interior.
In the deployed position, the louvers are no longer stacked and, consequently, a narrower channel can accommodate the louvers. The maximum thickness of the curtain in the deployed position is equal to the width of one horizontal flange plus the thickness of one vertical flange. Because the channels of the tracks are wide enough to accommodate the stacked louvers, the deployed curtain has room to move laterally within the channels and to allow a person to lift the curtain and gain access to the covered opening. To address this problem, Alligood provides two manual mechanisms which essentially narrow the channel when the curtain is deployed to prevent substantial lateral movement of the louvers within the channel.
In a first embodiment, a pair of hinged plates are provided, with each plate running parallel and connected by hinges to one of the tracks. The plates are provided with notches corresponding to horizontal flanges of the louvers extending rearwardly in the channels. After the louvers are deployed, the hinged plates are manually positioned in the channels by rotation about the hinges. In this position, the notches in the plates engage the corresponding horizontal flanges to prevent substantial lateral or horizontal movement of the louvers.
The Alligood patent discloses an alternative mechanism in the form of elongated locking angle members. Each of the angle members is located within one of the channels with a lower end pivotally connected to the track proximate the bottom of the channel. The point of connection is located at a distance from the front wall of the track slightly greater than the width of the deployed curtain. In the retracted position, an upper end of the angle member is placed against the back wall of the track to accommodate the stacked louvers. In the deployed position, the upper end of the angle member is manually rotated into position against the louvers and is locked in place by securing the upper end to the side wall of the track.
While these mechanisms effectively provides bracing for the louvers, the manual nature of these mechanisms presents challenges in operation. For example, the hinged plate mechanism requires access from the inside of the cover to rotate the plate into position and, therefore, cannot be used with windows that cannot open, such as plate glass windows on store fronts. Additionally, covers using the angle member mechanism wherein the locking pin or bolt is inserted from the outside of the cover will be difficult to lock when mounted on windows on the second floor or higher. Therefore, a need exists for a mechanism for bracing the curtain which is automatically engaged when the louvers are deployed to cover an opening.
The Alligood patent also discloses that the louvers are suspended in a desired spaced relationship by crimping stop-like members, for example mechanical pop-rivets, to support cables which extend through aligned holes in the louvers. The stop-like members prevent the louvers from moving in the downward direction along the cables, but do not prevent a louver from being lifted upwardly away from the next lower louver, thereby exposing the opening.
To prevent separation of the louvers and to strengthen the curtain, vertically disposed reinforcing members, or unitizing bars, are positioned periodically in engagement with the louvers. These unitizing bars are manually placed in contact with the louvers to prevent relative vertical movement of the deployed louvers. However, as with the locking mechanisms, the unitizing bar presents a difficulty in application for windows that do not open and some windows located above the first floor. Therefore, a need exists for an improved mechanism for preventing separation of the deployed louvers.